Aluminosilicate zeolite and other catalysts have been employed to convert methanol and/or dimethylethers to hydrocarbons, such as methanol to gasoline (MTG processes). The productivity of methanol conversion processes is limited primarily by the limits of the catalyst itself, which deactivates upon continued service due to, for example, the presence of steam, which in turn causes dealumination of the zeolite. The steaming conditions are inherent to a methanol and/or dimethylether conversion process and depend upon the total amount of methanol or oxygenate processed during the catalyst life, since one mole of water is generated for every mole of methanol or dimethylether converted.
MTG processes can generally yield, for example, between only 0.2 and 2 g hydrocarbon per g catalyst hour. As a result, catalyst costs are high.
Heat management is also a capital intensive endeavor, which is especially true in methanol conversion processes, such as MTG processes. Often, there is a need for large amounts of recycle solely to control heat, as the reaction from methanol to gasoline and distillate is highly exothermic. It is desirable to reduce the heat release in the first reaction stages in a MTG process.
In order to provide a methanol to gasoline process with increased economic feasibility, there is a need to improve the output of catalysts and to better manage the heat produced during the process in order to reduce heat recycle requirements.